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The Colombian Andes (CA) are located over the northwestern corner of tropical South America (NW‐TropSA), where land and atmosphere interchange moisture and energy in a complex way owing to the orographic influence on the recycling of moisture over land. We aim to understand where and when water vapor evaporated from land turns into rainfall through moisture recycling, using the Water Accounting Model‐2layers (WAM‐2), an offline model to track atmospheric moisture forced with data from ERA‐5 at its native 0.25° resolution during 1980–2020. We define the spatiotemporal distribution of sources (high evaporation recycle ratios, ϵC) and receptors (high precipitation recycle ratios, ρC) of continental moisture at diverse timescales, including monthly, seasonal, annual and interannual (ENSO). Referring to the regional runs of WAM‐2 over NW‐TropSA (4°S–12°N/80°W–66°W), at elevations above 1,000 m.a.s.l., the CA has a mean annual ρC of 11% (ranging 6%–16%) and a mean annual ϵC of 35% (ranging 27%–40%). Moisture recycling in the CA exhibits a strong annual cycle over the region. The seasonal dynamic of moisture recycling shows two clear‐cut sources of moisture: the eastern foothills of the Eastern and Central ranges of the CA. Both foothills are also regions of high rainfall, although moisture recycling mechanisms differ. Sources of continental moisture grow spatially during September‐October‐November and March‐April‐May. The seasonal availability of moisture recycled coincides with regions where orography interacts with low level jets sourcing humidity. At interannual timescales, sources and receptors of continental moisture in the CA are modulated by the extreme phases of ENSO. Key Points The orography of the Colombian Andes emerged as a critical factor shaping the interaction between land and atmospheric moisture fluxes Foothills and valleys of the Colombian Andes play a pivotal role in continental moisture recycling, in terms of convergence and divergence ENSO modulates both sources and receptors of continental moisture at interannual timescales

High-elevation wetlands in South America are not well described despite their high sensitivity to human impact and unique biodiversity. We describe the hydroclimatological and limnological characteristics of 21 wetlands on the High Andean Plateau of Argentina, synthesizing information gathered over ten years (2010–2020). We collected physical-chemical, phytoplankton, and zooplankton data and counted flamingos in each wetland. We also conducted an extensive analysis of climatic patterns and hydrological responses since 1985. These wetlands are shallow, with a wide range of salinity (from fresh to brine), mostly alkaline, and are dominated by carbonate and gypsum deposits and sodium-chloride waters. They tend to have high nutrient concentrations. Plankton shows a low species richness and moderate to high dominance of taxa. Flamingos are highly dependent on the presence of Bacillariophyta, which appears to be positively linked to silica and soluble reactive phosphorus availability. Climatic conditions show a strong region-wide increase in average air temperature since the mid-1980s and a decrease in precipitation between 1985–1999 and 2000–2020. These high-elevation wetlands are fundamentally sensitive systems; therefore, having baseline information becomes imperative to understanding the impact of climatic changes and other human perturbations. This work attempts to advance the body of scientific knowledge of these unique wetland systems.

Hydroclimatic variations in mid‐latitude Asia during the early to mid‐Holocene and associated mechanisms remain disputed, hampering our understanding of atmospheric circulation controls on regional climatic changes. We report Holocene alkenone records from two Siberian lakes, documenting lake temperature and hydrological changes, and synthesize records from mid‐latitude Asia to address regional hydroclimatic variability. Relatively dry conditions occurred in westerlies‐dominated regions and extended to marginal monsoon regions before ∼6,000 a BP, followed by wetting transitions during ∼6,000–5,000 a BP, despite contrasting temperature variations between two regions. We suggest that early to mid‐Holocene drought in mid‐latitude Asian interior appears to be associated with enhanced anticyclonic system over mid‐high latitude Eurasian continent, induced by prevailing cold airmasses, which extended its hydrological control to marginal monsoon regions. Our findings explain the spatial heterogeneity of hydrological changes in mid‐latitude Asia, and opposite temperature‐moisture associations within westerlies‐dominated and marginal monsoon regions during the early to mid‐Holocene.

• The long-lived tree species Eschweilera tenuifolia (O. Berg) Miers is characteristic of oligotrophic Amazonian black-water floodplain forests (igapó), seasonally inundated up to 10 months per year, often forming monodominant stands. We investigated E. tenuifolia′ growth andmortality patterns in undisturbed (Jaú National Park - JNP) and disturbed igapós (Uatumã Sustainable Development Reserve - USDR, downstream of the Balbina hydroelectric dam). • We analysed age–diameter relationships, basal area increment (BAI) through 5-cm diameter classes, growth changes and growth ratios preceding death, BAI clustering, BAI ratio, and dated the individual year of death (14C). Growth and mortality patterns were then related to climatic or anthropogenic disturbances. • Results were similar for both populations for estimated maximum ages (JNP, 466 yr; USDR, 498 yr, except for one USDR tree with an estimated age of 820 yr) and slightly different for mean diameter increment (JNP: 2.04 mm; USDR: 2.28 mm). Living trees from JNP showed altered growth post-1975 and sparse tree mortality occurred at various times, possibly induced by extreme hydroclimatic events. In contrast with the JNP, abrupt growth changes and massive mortality occurred in the USDR after the dam construction began (1983). • Even more than 30 yr after dam construction, flood-pulse alteration continues to affect both growth and mortality of E. tenuifolia. Besides its vulnerability to anthropogenic disturbances, this species is also susceptible to long-lasting dry and wet periods induced by climatic events, the combination of both processes may cause its local and regional extinction.

Landscape and climate alterations foreshadow global-scale shifts of river flow regimes. However, a theory that identifies the range of foreseen impacts on streamflows resulting from inhomogeneous forcings and sensitivity gradients across diverse regimes is lacking. Here, we derive a measurable index embedding climate and landscape attributes (the ratio of the mean interarrival of streamflow-producing rainfall events and the mean catchment response time) that discriminates erratic regimes with enhanced intraseasonal streamflow variability from persistent regimes endowed with regular flow patterns. Theoretical and empirical data show that erratic hydrological regimes typical of rivers with low mean discharges are resilient in that they hold a reduced sensitivity to climate fluctuations. The distinction between erratic and persistent regimes provides a robust framework for characterizing the hydrology of freshwater ecosystems and improving water management strategies in times of global change.

Due to its potential geo-political and environmental implications, climate migration is an increasing concern to the international community. However, while there is considerable attention devoted to migration in response to sea-level rise, there is a limited understanding of human mobility due to freshwater and inland hydroclimatic changes. Hence, the aim of this paper is to examine the existing evidence on migration as an adaptation strategy due to freshwater and inland hydroclimatic changes. A meta-review of papers published between 2014 and 2019 yielded 67 publications, the majority of which focus on a handful of countries in the Global South. Droughts, floods, extreme heat, and changes in seasonal precipitation patterns were singled out as the most common hazards triggering migration. Importantly, most of the papers discuss mobility as part of a portfolio of responses. Motivations to migrate at the household level range from survival to searching for better economic opportunities. The outcomes of migration are mixed — spanning from higher incomes to difficulties in finding employment after moving and struggles with a higher cost of living. While remittances can be beneficial, migration does not always have a positive outcome for those who are left behind. Furthermore, this meta-review shows that migration, even when desired, is not an option for some of the most vulnerable households. These multifaceted results suggest that, while climate mobility is certainly happening due to freshwater and inland hydroclimatic changes, studies reviewing it are limited and substantial gaps remain in terms of geographical coverage, implementation assessments, and outcomes evaluation. We argue that these gaps need to be filled to inform climate and migration policies that increasingly need to be intertwined rather than shaped in isolation from each other.

Seasonal prediction of Indian Summer Monsoon Rainfall (ISMR, rainfall during June to September over India) has remained an important scientific challenge for decades, due to its complex multi-scale nature. Statistical and dynamical seasonal ISMR predictions have traditionally relied on the relatively small variability of the spatially averaged monsoon rainfall over India, known as All India Monsoon Rainfall (AIMR). While this has served to mitigate socioeconomic impacts to some extent, overall prediction skill has remained relatively low (Wang et al. in Nat Commun 6:7154. https://doi.org/10.1038/ncomms8154 , 2015) while the spatial variability is anything but small. Here we find that the classification of deficit/ dry or surplus/ wet monsoon years based on AIMR does not add value at a regional scale due to the very high heterogeneity of monsoon rainfall, even in the extreme years. To demonstrate the need and the potential to predict this important spatial heterogeneity, we improve the classification of monsoon years by focusing on the spatial patterns of rainfall anomalies within different meteorological subdivisions of India. We apply the k -means clustering methodology and also offer cluster validation. Cluster validation reveals the existence of nine clusters of monsoon years with distinct spatial patterns of monsoon rainfall anomalies. The composite anomalies of sea surface temperature (SST) and winds during March to May (MAM) and June to September (JJAS) show distinct hydroclimatic teleconnections indicating potential predictability of regional monsoon rainfall at seasonal scale. To demonstrate the potential prediction pathways for spatial patterns of ISMR, we develop a statistical seasonal prediction model based on Classification and Regression Tree (CART) between SST over different oceanic regions as predictors and monsoon classes as predictands for the period 1901–2010. Search for the potential regressors reveals the importance of new predictors such as Atlantic Niño and SST over North Pacific region along with conventional predictors such as El Niño Southern Oscillation (ENSO), Indian Ocean Dipole/Zonal Mode (IODZM), etc. Validation of the method is performed for 2011–2015 and the model is able to predict the regional pattern of monsoon rainfall for 4 out of the 5 years. The purpose of this prediction exercise is to demonstrate the need to focus on the process and predictive understanding of these clusters and their predictability.

Senegal, like many West African countries reliant on natural resources and agriculture, faces severe impacts from climate change. This study provides an analysis undertaken by the United States Agency for International Development (USAID) under the Senegal Water Resources Management Activity, investigating historical and projected rainfall extremes to assess potential risks to water resources under future climate scenarios. Using bias-corrected CMIP6 data validated against the Enhancing National Climate Services (ENACTS) dataset for 1985–2014, we assess model performance through time series analysis, spatial distribution, and Taylor diagrams. We examine changes across three time periods—1985–2013 (historical), 2021–2040 (near future), and 2041–2060 (distant future)—focusing on nine key rainfall indices relevant to agriculture and water security. The results indicate that CMIP6 models capture historical rainfall patterns well. The models MPI-ESM1-2-HR, MIROC-ES2L, MRI-ESM2-0, CanESM5, and GISS-E2-1-G show the best performance and are recommended for climate impact assessments. Spatial analysis reveals prolonged dry periods in the north and heavier rainfall in the south. Under SSP585, the near future shows an increase in consecutive dry days (CDDs) and a decline in extreme rainfall events in northern Senegal, whereas the distant future projects a reversal with intensified rainfall (Rx5day). The south shows contrasting patterns, with increasing rainfall intensities in the long term. These findings highlight shifts in rainfall regimes and underscore the urgency of integrating future climate scenarios into adaptation planning. This study recommends extending analysis to temperature extremes due to their implications for agriculture and public health.

Hydroclimatic variability has increased in recent decades across the southeastern US, with more frequent droughts and heavy precipitation events. Among these extremes, past research reveals that there is much variety in the synoptic-scale circulation that controls warm-season precipitation. However, research has yet to examine the subtle variation between these circulation patterns and their influence on hydroclimate variability. This is particularly the case in the southern Appalachian Mountains, where topographic complexity mediates the relationship between large-scale circulation and precipitation characteristics. In this study, we use a self-organizing map to classify and spatially visualize synoptic-scale circulation patterns over the southeastern US from 1979 to 2014. The patterns identified in the self-organizing map are linked with daily precipitation characteristics in the region. Our results demonstrate that underlying topographic features have a marked influence on the hydroclimate, and this influence varies according to the configuration of circulation. Greater frequencies of light precipitation are observed across broad-scale regions of high elevation, to varying degrees, no matter which circulation pattern is present. In contrast, precipitation frequencies along interior valleys and leeward slopes are lower and largely limited to a subset of circulation patterns. This study demonstrates how shifts in the large-scale circulation are likely to alter the occurrence of different types of warm-season precipitation events across mountain catchments.

Reservoir construction has led to the development of numerous wetlands, and these wetlands play an important role in global environmental change. In this paper, we investigate the relationship between reservoir wetlands and hydroclimatic variables. We used the MODIS land cover product to extract the wetland area of the Sanmenxia Reservoir, China. Then, various indices of reservoir wetland landscape patterns were calculated. Principal component analysis was performed to build the Sanmenxia Reservoir wetland comprehensive landscape pattern index (CLPI) to depict the changes in Sanmenxia Reservoir wetlands from 2001 to 2013. Pearson correlation analysis was used to assess their relationship. The following results were obtained. Firstly, the Sanmenxia Reservoir wetland area considerably declined and the landscape heterogeneity decreased from 2001 to 2013, especially in 2004. Secondly, the CLPI is significantly negatively correlated with annual runoff and significantly positively correlated with annual sediment discharge, annual average water level and annual shallow groundwater table in Sanmenxia Reservoir regions. Additionally, due to the decline in the reservoir wetland area, the values of Shannon’s diversity index and Simpson’s diversity index decreased in the study area. Therefore, the study suggests that maintaining a stable and healthy reservoir wetland area should be the focus of ecological reservoir management.